Doping and compensation in heavily Mg doped Al-rich AlGaN films
Pegah Bagheri, Andrew Klump, Shun Washiyama, M. Hayden Breckenridge, Ji Hyun Kim, Yan Guan, Dolar Khachariya, Cristyan Quiñones-García, Biplab Sarkar, Shashwat Rathkanthiwar, Pramod Reddy, Seiji Mita, Ronny Kirste, Ramón Collazo, Zlatko Sitar
Abstract
Record low resistivities of 10 and 30 Ω cm and room-temperature free hole concentrations as high as 3 × 1018 cm−3 were achieved in bulk doping of Mg in Al0.6Ga0.4N films grown on AlN single crystalline wafer and sapphire. The highly conductive films exhibited a low ionization energy of 50 meV and impurity band conduction. Both high Mg concentration (>2 × 1019 cm−3) and low compensation were required to achieve impurity band conduction and high p-type conductivity. The formation of VN-related compensators was actively suppressed by chemical potential control during the deposition process. This work overcomes previous limitations in p-type aluminum gallium nitride (p-AlGaN) and offers a technologically viable solution to high p-conductivity in AlGaN and AlN.